1. Field of the Invention
The present invention is directed to the field of matable electrical connector assembly blocks for establishing electrical circuits between pairs of conductors. More specifically, the present invention is directed to that portion of the above noted field which is concerned with the mechanism by which matable connector block members are maintained in assembled relationship. More particularly still, the present invention is directed to that portion of the above noted field which is concerned with mechanisms by which matable pairs of connector block members held in assembled relation by latching means of the overcenter locking type may be easily intentionally separated while maintaining a positively locked relationship when separation is not intended.
2. Description of the Prior Art
Matable electrical connector blocks which house pairs of mutually engagable electrical connector contacts and which are operative to maintain the contacts or terminals in an engaged relation are well known. Since the electrical contacts are usually recessed within the various portions of the electrical connector body it is known to be necessary to tightly engage the connector bodies to be sure that the electrical contacts are in an operable mutually engaged and conducting relationship. This connection may be assured in a variety of ways such as by providing mutually engagable screw and nut mechanisms on the sides of the connectors or by providing threaded connections between the pairs of matable connectors. Another form of assuring that the matable connector blocks are suitably engaged to provide for positive connection between the electrical contacts is to provide overcenter locking or latching apparatus. FIG. 1 of the drawing of this application illustrates one well known form of overcenter locking mechanism.
Connector blocks such as illustrated in FIG. 1 are frequently provided with a plurality of pairs of mutually interengagable electrical contacts which are intended to carry significant amounts of current which may reach values of several amperes or higher. These high values of current are frequently carried by bayonet type male contacts which are received between a pair of resiliently biased female contacts in the operative mode. In order to assure adequate contact between the pairs of contacts carrying high values of current it is normally the practice to provide a relatively high spring force between the contacts. This dictates that the overcenter locking mechanism provided with the connector blocks be arranged so that when the overcenter condition is reached a sufficiently high connecting force is generated to overcome any expected level of friction generated resistive force produced by the high level of spring force acting between the various pairs of electrical contact members.
In order to overcome the above noted high levels of resistive forces generated between the electrical contact members, overcenter locking mechanisms such as illustrated in FIG. 1 are normally comprised of at least one double ramp member situated on a first connector block member and at least one lever arm latching member situated on the mating connector block member. The latching member is engagable with the double ramp member when the connector is assembled. The double ramp member is normally provided with a first relatively gradual ramp surface which the lever arm latching member will initially engage when the matable connector block members are assembled and a second relatively steep rear ramp surface which provides an abrupt drop off. The connector block members are normally made of a relatively rigid plastic material having a high dielectric constant with the lever arm latching member capable of generating a relatively high degree of force when deflected through a small angle. The force is generated primarily by deformation of the latching member. Thus, the shallow or gradual ramp surface is operative to spread the lever arm member away from its normal position under the application of a relatively small degree of assembly force operating over an extended distance and the rear ramp surface is operative to rapidly accelerate the matable connector block members together once the overcenter position has been passed by dissipating the stored force over a relatively shorter distance. This mechanism is also operative to provide for complete separation of the two connector block members in the event that the overcenter position is not reached so that the connectors are forcibly separated and the lack of electrical circuit can be visually detected by the absence of mating of the two matable connector block members.
The structure briefly described hereinabove results in the anomalous situation that the connector block members may not be easily separated in order to accomplish any necessary servicing which may be required of the electrical apparatus assiciated with the circuits passing through the connector block members. This problem is further made more difficult by the fact that these connectors are frequently used to pass electrical current through wall structures under circumstances which make the connector relatively inaccessible once it has been installed in use. In those instances where more than one overcenter locking mechanism is provided on any one pair of matable connector block members it is normally the case that special tools are required to separate the connector block members with force levels being generated which approach levels sufficiently high to fracture the plastic. It is therefore a specific object of the present invention to provide an improved overcenter locking apparatus for pairs of matable connector block members which will operate in the same manner and with the same degree of reliability as prior overcenter locking mechanisms but which will be readily disengageable to permit easy intentional separation of the connector block members.
One way of accomplishing the general objectives set forth hereinabove would be to provide a rearwardly extending lever arm mechanism which could be gripped to forcibly move the double ramp member engaging end of the latching member outwardly away from the connector block member having the double ramp portion to facilitate the disassembly of the connector block members. As a practical matter however this is not possible due to the fact that the material forming the rearwardly extending portion would be deformable to the same degree that the forwardly extending latching member is deformable. Thus, even with a very long rearward extension, the lifting force necessary to overcome the resistance to deflection of the latching member and any binding with the double ramp portion could not be generated. It is therefore a further object of the present invention to provide a mechanism by which matable connector block members may be easily separated, which mechanism does not significantly increase the physical size of the connector block members and the space required within any associated housing structure to receive the connector block members. It is a further object of the present invention to provide an overcenter latching mechanism having improved release operation which may be integrally molded with the dielectric material normally utilized to form the matable connector block members.